Process for reconditioning iron and steel drums



1 man Dec. 18, 1928.

UNITED STATES ROBERT c. nmzxan,

Io Drawing.

' This invention relates to cleaning and coating of metal drums suchas. are used to contain various liquids as alcohol-and other liquids.

5' I More particularly th; invention relates i [a process for reconditioning such iroh and steel shipping drums which have become rusty on their interior from use or abuse.

It is a well understood fact that drums of this, character are liable to have their interiors very badly rusted and in many instances these drums cannot be used-a second time until all such rust has been removed.

Among the important-objects of the present invention is to provide an improved process whereby. not only will the rust beremoved from the drums but a coating will be provided on the interior which is rust proof and insoluble in ordinary liquids.

A second important object of the invention is to provide an improved whereby the cleaning and coating wi be performed in a single operation. 1 I f With the aboveand other objects in view as- .will be hereinafter understood, the invention in its present embodiment is carried out in the following manner: I

- In the rusty drum is placed an aqueous solution of oxalic acid whlch unites with the rust to form an iron oxalate. After the formation of the oxalate there is placed the drum an aqueous solution of a metallic acetate 'in which the metallic element is replaceable by the iron of the irdnoxalate when the 5 acetate and oxalate are brought into contact,

This .will form one of the basic acetates of iron and the process may be expedited bythe of steam:

40 As a specific example of' the method .which the process is carried out, in the rusty drum, which has been emptied of its contents, is laced an aqueous solution of oxalic acid. It is found that a suitable strength of such solution may be obtained by dissolving 17 unds of oxalic acid in 40 gallons of water.

Pin to be noted that while this solution it '5 application of heat-eitherdry or in the form this s ution, the quantity or cmcnma'rr, omo.

brnocnss' ron. nncoxnrrronnio morrarrn Bram. mums.

I hpplicatien fled mm 151m. Serial a. 220,405.

suitable one I'do not confine myself in all instances to the precise strength of solution herein set forth as this ma vary in accord- 5o ance with the conditions 0 the drums beingtreat ()rdinaril there is placed in a drum 0 the gal on-size about 1 quart of a of the solution va ing somewhat with the extent of rusting 55 an 0 course, varying with the size of the drum." This solution, by some suitable means, is distributed or spread all over the. interior surface of the drum. The solution of oxalic acid in contact with the oxide of do iron forms with such oxide an iron oxalate, such as ferrous oxalate, ferric oxalate or com- .plex ions of ferrous and ferric oxalate;

After the oxalic acid hasbeen spread over' the interior the drum. is heated by the appliee' cation of live steam and this may be done in any convenient manner such as the filling of a. chamber in which the drum is inclosed by such live steam, the drum being openl so that the steam may enter the interior. Next the aqueous solution of aluminum acetate. is placed-in the drum andsprea'd' around the walls to cover the entire inner surface. This aluminum acetate unites with the oxalate on the wallsto form a rust resisting, water proof coatin covering the entire interior of the drum. t'is'a well-known fact that under certain-conditions the mixture of an acetate 'such as aluminum acetate with an oxalate of iron will form a basic acetate of iron of which there are several forms and some of these .formsare highly insoluble and when dried present a lassy appearance. The presence of such aic' acetate is somewhat-difiicult to'determine but it is probable that the coat- 8B a solution of oxalic acid evenly over t rior surface of the drum, heating the drum, and then afpplying aluminum acetate to the treated sur ace.

3. That process of'reconditioning interiorly rusted drums which consists in a plying lie interior surface of the drum, filling the drum with live steam, and then applying aluminum acetate to the treated surface.

ROBERT C. HEINZMAN. 

